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    <blockquote> <p>whether it is a bad practice to skip equals and hashCode altogether</p> </blockquote> <p>Yes. You should <em>always</em> override your equals and hashCode. Period. The reason is that this method <em>is</em> present already in your class, implemented in Object. Turns out that this implementation is generic, and nearly 100% of the times it's a wrong implementation for your own objects. So, by skipping equals/hashCode you are in fact providing a wrong implementation and will (in the best case scenario) confuse whoever uses these classes. It may be your colleagues, or it may be some framework you are using (which can lead to unpredictable and hard-to-debug issues).</p> <p>There's no reason to <em>not</em> implement these methods. Most IDEs provides a generator for equals/hashCode. You just need to inform the IDE about your business key.</p>
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    1. COHello ! Thanks for the insight. I understand that IDE can help generating it, and there is jakarta common lang EqualsBuilder or HashCodeBuilder for that. But i were just thinking whether it's a bad idea to skip it if im satisfied with the default Object.equals() and Object.hashCode(), using the == for equality. Because once i decide to implement eq/hC, that adds a bit of cost of implementation and future maintenance. Your arguments make sense, but what about the business key fields that can be changed ? I think although most business key fields wont change, but perhaps some can change ?
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    2. COBusiness keys *can* change, and that's fine. That's why you are using a surrogate key :-) But usually, if the business key change to add a new property to the key, it means that your application will be redeployed. Thus, there's no problem there, as all existing objects will leave the JVM and will be loaded with the new property. And if a specific object has its own business key changed, it means it's not equal anymore to other objects with the same business key. Which is quite appropriate. So, you have nothing to lose by implementing equals/hashCode.
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    3. COSorry for not being clear with my latest response. I was thinking about modifying an already existing record in db. Because according to the article, using the id in eq/hC is not enough in some cases for hibernate, so the eq/hC based on business key fields is introduced. So, i was thinking, if the business key values can be changed, how can i find the old entity inside a collection that still have the old business key values and then replace it with the new values ? This seems that i have to use the id instead to be able to locate the old entity and change the business key values.
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